2 questions about reinstalling windows 7

So I have problems with the current 7600 build of windows 7, so i was wondering if I downgrade to build 7127 will some of the programs not work on it, in general what's the difference?

I want to do that, because I have problems with my connection dropping, you can see my thread about it here Network connection dropping while downloading with utorrent? - Windows 7 Forums

so I read that 7127 build seems to not have those problems and I was wondering about giving it a try since I can't fix this problem even though I tried various ways my connection is still dropping.

also, when I usually reinstall windows I choose an option where my old windows folde is renamed to .old and I keep my files, so I was wondering if that installation is even 'clean' so for example if I had my current windows infescted would installing it like this 'clean' my system, or not? I was wondering because it's all in windows' folder anyway and when you install a new OS you have a new clean folder, but I just wanna make sure I'm right.
If not, can anyone please tell me if there's a way to format my disk, but without having to delete the files I have on my computer? I'm asking because theres' no way I could put all my stuff on cd's and then put it back on my comp. It's too much stuff.
And if there is, how do I do it?

I don't know whether 7127 (nonpublic RC branch build, I think) will run now. I believe that it would have the same expiration as the RC, which was in June of 2010. (I suppose someone has hacked it to avoid that, though.)

If you want to switch OSes, an external HD is pretty much a necessary investment, to allow you to preserve your files.

Doing a "custom" install creates the windows.old folder. I wouldn't count on it to get rid of a virus infection, though. A real reformat would be safer.

Maybe utorrent would run better with un unhacked version of the RTM release. I've run it (infrequently) with no problems under Win7 X64. Sometimes reliability isn't free.

If you have a legal copy of Windows 7, I apologize. (Seems unlikely, though.)

bobkn said:

I don't know whether 7127 (nonpublic RC branch build, I think) will run now. I believe that it would have the same expiration as the RC, which was in June of 2010. (I suppose someone has hacked it to avoid that, though.)

If you want to switch OSes, an external HD is pretty much a necessary investment, to allow you to preserve your files.

Doing a "custom" install creates the windows.old folder. I wouldn't count on it to get rid of a virus infection, though. A real reformat would be safer.

Maybe utorrent would run better with un unhacked version of the RTM release. I've run it (infrequently) with no problems under Win7 X64. Sometimes reliability isn't free.

If you have a legal copy of Windows 7, I apologize. (Seems unlikely, though.)

thanks everyone for your answers.
yeah, I've been thinking about external HD, but haven't gotten around buying it yet, probably gonna do that soon.

I thought so the real reformat would be safer, but as I mentioned, I can't delete some of the files on my comp.

What do you mean by 'uhacked'? Where can I get this?
But I have x86 version, maybe that's te problem..however I can't run x64 one as my processor is 32 one.

Petey7 said:

"unhacked" means one that has not been tampered with. He means, where did you get you copy of Windows 7 from? Did you actually buy a retail copy? Did you get it through MS's student only deal? Or did you download it from a torrent site?

I got it from a torrent site. So what can I do to have 'unhacked' version, is there a torrent for it?
I usually do torrents before I buy a retail.