How do I get my computer to boot?

My computer has been working fine, until recently, say the past week, I turn it on, use it for a while and then it would turn itself off. It's not connected to the internet so I didn't think it could be a virus.



However I tried to turn it on yesterday and it wouldn't even get to load all the way before it turned itself off. Now when I turn it on it shows the acer screen as it should, then beeps as it should and then I get a message which says:



Invalid BOOT.INI file

Booting from C:\windows\



I have been on other forums and seen that many answers say they either need a disk to boot it from (which I don't have) or that they need to change the BOOT thing but I can't do that because my computer won't load. It will just sit at the Invalid BOOT.INI screen for hours.



I'm hoping there is a way I could fix this problem without having to spend a lot of money.



Thanks



Oh and my computer runs on Windows XP home edition.How do I get my computer to boot?
Borrow a Win XP home CD from a friend. Use the Recovery consol and at the C prompt type ';fixboot'; without the quotes.



wdwHow do I get my computer to boot?
Ok! This is a bit complex! First of all, if possible try to get a copy of the boot disk for the formatting purpose. This you can generally find on torrents I suppose. Else, try logging into Safe mode pressing F8 key as soon as you see the acer screen and try to recover the previous settings . I just have this much amount of information. :( Hope this helps.
try reinstalling / repair using win xp.