Helpcis idk

well my computer has a few problems,

-sometimes when i turn it on it immeaditly turns off, maybe cuz i need to let it load before i turn it on?

-when i open my msn, sometimes it closes and says reconnecting in X minutes, my internet connection is fine. i tried deleting and reinstallin but still same problem

-sometime mozilla firefox acts liek a real di*k, it has been gettin alot of problems, and says “dont send, and send error report thing”

-sometimes mozilla firefox erases my favorites the next day i put them, i tried deleting and reinstalling, but same problems.

-most of the time on my dock next to the clock, it shows this icon that is a .gif and first it has a pit of the word with the windows icon littler in the top left, then it turns to a yellow square with a ballon inside and often says- Critical Stem Errors!: System Detected virus activities. please buy an anti virus pogram and blah blah blah. when i press it it takes me to http://www.virusbursters.com/?aff=334
i dont know y that link dont work, it used to, it used to be “download this antivirus pogram for like 30 dollars”(i dont know if this is advertising). i already have zone alarm and i check for spyware/viruses every week, and it says theres none, or it says that it deletes the viruses/ spyware, but i still get that critical system error. sometimes i dont see it but then if i restart my pc it shows it.

-sometimes my pc gets in a blue page the whole window: and it says something went wrong, maybe it has something to do with ur software or hardware, but there both fine, -_-

i saw this site and thought it would be really kool and maybe would get good replies to help me.

please help, i beg of u!

p.s. i have windows XP