It's worthy trying to physically clean the dust out, but if you want to replace windows..
The way I do it is start with a windows OEM ISO from TPB.
I believe these ones will have their hashes match an original OEM disk (no virii, unless microsoft put it there, also uncracked to start)
Ultimate X64 64bit;
http://thepiratebay.se/torrent/6187012
Ultimate X86 32bit;
http://thepiratebay.se/torrent/6187014
Professional X64 64bit;
http://thepiratebay.se/torrent/6187008
Professional X86 32bit;
http://thepiratebay.se/torrent/6187011
Home Premium X86 32bit;
http://thepiratebay.se/torrent/6187006
Home Premium X64 64bit;
http://thepiratebay.se/torrent/6233968
Home Basic X86 32bit;
http://thepiratebay.se/torrent/6187005
Home Basic X64 64bit;
http://thepiratebay.se/torrent/6233969
Starter X86 32bit;
http://thepiratebay.se/torrent/6187007
Moar:
https://forum.suprbay.org/showthread.php?tid=86040
Then either burn the ISO to a DVD or my preferred method.. transfer it to a thumbdrive via
http://www.microsoftstore.com/store/mss ... vd_dwnTool
If you have an external drive, backup everything important (movies/music/docs/porn/etc). You may want to back up your windows serial key also.
There are driver backup tools, I don't personally use them. I normally just grab updated drivers from the manufacturers website when I do a fresh install. It's better to get at least your network drivers (so you can download the rest of the drivers once the machine is up if they aren't detected) throw them on the USB drive ahead of time then after you do a fresh install go to Start>Control Panel>Hardware and Sound>Device manager and select each unknown device, and then locate a fresh driver from your manufacturers web page for each one windows 7 does not automatically detect. You will want to get the newest video card drivers even if windows does detect yours.
Put the disk or usb drive in, make sure your BIOS is set to boot from it. I like to format and partition my whole drive and trash backup partitions (I don't use em) and repartition into one big drive to recover space (if not dual booting).
Once you are installed if you are using a version of windows you don't legitimately own, I've found daz loader to be a great activator/genuine advantage bypass.
http://forums.mydigitallife.info/thread ... nformation
Then run windows update and let it patch your system with the newest software, pull your backups back from the external, throw whatever else you need on (CS:S) and you're done. It's a pretty straightforward process, I taught my artist girlfriend to do it, so you should be able to figure it out.
"Most people think time is like a river, that flows swift and sure in one direction. But I have seen the face of time, and I can tell you, they are wrong. Time is an ocean in a storm."