Steam making my PC freeze?

I downloaded Steam today to play the Half Life 2 demo, and, after playing it for a bit then going to my desktop and then going on the Internet (FireFox) with Steam open as well, my PC slowed to near stop, then beeped (a single beep) every time I tried to do something (CTRL ALT DEL or close a program etc). Previous to that I had noticed there was alot of processes running in task manager, and alot of new ones/duplicates of the same .exe. My PC then completely froze (as far as I could tell) so I turned it off, and restarted. As Windows loaded and I saw my desktop it showed me a message saying ''A file from your system registry (something like that system registry or similar) was missing (or corrupted, something along those lines) but was successfully replaced with a backup or alternate saved version'' (it was something like that, I didn%26#39;t really pay much attention as it said it was successful). After downloading another demo off Steam, I decided to buy HL2: Ep1 (along with the package of Lost Coast, Deathmatch etc). It had been downloading for a bit when my computer froze (stopped completely no slow down this time). I turned it off and started again, only to have it freeze again about 2 minutes later. I%26#39;m currently writing without Steam running, and it has obviously not frozen yet. My PC is relatively new (less than 2 months old) built by myself, and has run fine since I built it (never had the PC freeze out of the blue e.g. whilst running simple apps excluding games). Is Steam causing this issue, or is it the missing registry thing (and was that caused by Steam) causing these freezes. And what can I do about it if it is, seeing as I have just purchased Half-Life and all. Thanks.Steam making my PC freeze?
That's one of the reasons why I can't stand Steam - Sometimes it will use 100% cpu power no apparent reason, which makes your entire PC really really slow for. It doesn't happen if you play any Steam game, but if you surf around or view some movies etc. it just starts sucking the force outta your pc.. No idea why.Steam making my PC freeze?
Yeh, I kinda felt that, when playing the demos it ran fine, but going on FireFox and scrolling it just got slow, it seems like one of those apps that just drains you%26#39;re PC, thats why I was hesitant about getting it. Aslong as HL runs ok once it%26#39;s downloaded I will be ok, as by the time I buy another game off there I will have gotten a new PC (maybe HL2: Ep2 and 3 if they come out soon, but I can stand downloading them while leaving the computer). I just feel it has helped my PC along the way to getting messed up, just corrupting files and messing things about draining resources etc, everything that puts you down the road to a reinstall of XP. Steam seems like a good piece of software, almost too good.

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