I've never heard of PC booster, and it certainly wouldn't guarantee to fix that issue. I can't access that site here, but if it's a commercial, paid for suite I'd class the above post as spam, especially since it's your first one.
It's correct that it could certainly be something odd with the registry. On that front I'd recommend running CCleaner - it's free, does a good job and it's a well known, well respected tool. It's also worth running Spybot S&D, some form of virus / malware may have caused havoc.
That said, it's not always possible to fix this issue without a complete wipe / reinstall - and if you spend more than a day or so figuring it out, that's personally the route I'd go down. Doesn't take long, and these days it's often far quicker (and gives you a clean install to boot) than trawling through system files and registry entries for weeks on end in the hope you can sort things out.
i have to agree with berry on this ccleaner is the way to go although ive never used spybot its always good to check virus/ malware
good answer berry now maybe you can tell me how they fixedthe problem with vista home prem 32 not starting up just bein on blank screen?