Hi, i have been having problems with my new windows 7 home

. Just like many other members on here infact all sound like we have mostly the same problems.
The problem pretty much is starting up windows7 its either :
a:gets stuck on the windows 7 loading screen (so i just restart)
b:the compuet just restarts it self automatically before the windows 7 loading screen comes up.
After a few restarts it works just fine with no problems what so ever.
I use the start up repair program which it suggests (or whatever its called) and it comes up with no problems at all. Also ocassionally (2 times) have the bsod come up at start up with some messages which i havent quite caught yet something to do with .sys file or something.
I have tried a few guides on here for replacing missing fileswith the windows 7 disk which didnt work

. I just cant stand keep on restating the compuet about 3 times for it to work fine lol
If any one can help i would be so grateful

Thanks