For example: http://www.iobit.com/advancedwindowscarepro.html
(if this link is against forum rules i'll delete it)
So my PC keeps getting slower and slower i tried the basic steps such as defrag, registry cleaner... yeah that's about it. my problem is that i lack knowledge to try more advanced options, and patience to make backups and then sweep my harddrive.
has anyone evr tried one of these programs? are they actually worth it?

PC tuning programs that advertise like they magically make your computer faster are most definitely sketchy. The only kinds of optimization programs I use are usually the same old defrag tool and pretty much that's it.
Now, if your computer is getting slower like that, I suggest you do a full reinstall of your OS. Drastic, but it works. I know many people who do a complete cleanup like that, and it isn't as hard as you might think.

I've tried many of them (but not ioBit's) and never found them to do anything worthwhile. The only things that really improve your PCs performance are clearing junk files, defrags, hardware upgrades and OS re-installs.

I use a program called Boostspeed, it's a very comprehensive piece of software for the price. It does pretty much anything you could wish for from this kind of program and does it well. I have used it for a couple of years without any issues whatsoever.
I also use ccleaner which is free and allows you to clear your temporary files, cookies, start menu history etc. It also features a nice registry cleaner.
EDIT: IIRC if you want to give Boostspeed a try, you can download it and use if for 15 days before you actually purchase it.

Most of those are bullshit. Can't say that one is, but I personally wouldn't go for it.
I'd recommend using CCleaner to clean your pc, and also to remove (disable) some of the usually many programs that run on startup. This both makes your startup take much longer time, and can make your computer slower generally with the amount of programs running in the background.
Be careful though, only disable the programs you know you don't need.
Usually a google search for the file name gives you enough information to find out if you want to keep it.
Lastly, if you really want your PC fast and new, do a reformat. Just make sure to backup everything you want to keep.
I'll be glad to provide more details if needed.
EDIT:
Boostspeed up there looks slightly more promising. Auslogics is a fairly well-respected company. Their defragger [url]http://www.auslogics.com/en/software/disk-defrag[/url] is regarded as one of the best.

I'd also tend to say no.
From my experience the majority of the problem with PC slowdown is a fragmented swap file, it can't be defragged whilst active and so the best way is usually to remove the swap file entirely, defrag the drive then create a new swap, that should create it in the largest bit of contiguous space and with a minimum number of chunks.

If you're not willing to invest the one hour it takes to format and reinstall, you'll just have to live with a sloggy computer.

Its a LOT longer than an hour depending on the apps you have installed and your configuration.
Definitely worth ghosting the system when it'd done so you only have to do it once

If you have to spend a day reinstalling your system then that explains why it is sluggish in the first place. Stop installing 1827 useless or borderline useless apps. You won't believe how sluggish a Windows installation becomes just from having a bloated registry.
Also, don't ghost a system that is already performingly poorly. Wipe it clean, then ghost the clean system for future reinstalls.

Its not necessarily shitloads of useless programs, its getting the core ones to run and be tweaked to the exact way you want them. I'm very picky about my settings so it takes me a fair bit longer to set up.
Never ghost anything but a freshly installed system, to do otherwise is madness

I also think those softwares are nonsense. Well ok, they can delete some files (as can Windows tools too!) but allowing them to mess with already quite complex registry doesn't make me feel too good. I also think "having" to clean registry is bit 90's thing. Current Windowses should handle it quite neatly. Has anyone done any real benchmarks about what is the gain on those "tweaks" and where else it reflects? Especially the registry...
If there was a magic way to make Windows act many times faster year after year, I'd say it would be already implemented (and sued into oblivion by EU). Of course a GOOD defragger might come handy as Windows supplied tool is quite basic and clogs up with bigger files.
I personally dislike big maintenance mumbo jumbos and try to keep things simple. New drivers are in order from time to time for graphics card but other than that and automatic updates for AV & Windows, not much... I ran XP install from 2004 to 2007, then moved to Vista and took a fresh install to new hard drive. Now after 2 years, I took one more step to Win7 RC1 with yet new HD.
I think the "disable services" tweaking is bit unnecessary. Yes, there are lots of programs that install stupid things. You can also choose not to install those programs, like Adobe Reader that can be replaced neatly with Foxit Reader. Lots of those background services can be safely disabled via the program preferences. Memory is quite cheap too, so having a truckload of it isn't that bad idea. You can leave the fiddling aside and use the time being Creative than having maintenances once in a while. Darn, I've already began to sound like a Mac user...

It takes me about a day to get my PC back the way I want it after reformatting. I have around 10 must-have programs and they all need setting up.
EDIT:
I'm getting off-topic.
My point is that even though it can take some time, it's definitely worth it.

Concurred. Programs with low memory footprints like Foxit (which I use and love) can do wonders for computer performance, no matter how powerful and whatever specs the computer in question has.

I agree.
I really don't get how Adobe have managed to screw Reader that much up. They're obviously very able, just take a look at Photoshop or After Effects, both of which are more or less industry standards.

Foxit Reader is great. It's super-fast, whereas Adobe Reader (let alone Acrobat) is a slug.