what wrong with my system

[hoang101]

all the sudden my Winxp pro need cd in the drive to got it boot up, I check the bios still the same setting
Hardrive then Cdrom, and the floppy seeks on boot-up still disable, I try another small harddisk (4Gig) just have Winxp on and it prompt the same thing (invalid system disk...) so what is wrong? may be the bios? is there any fix that I could try? may be virus? and system is 3Ghz, HD 340G right now just have WinXP Pro, MS words and Norton system work 2004 ... TIA

 

[Wizkid]

Boot with the CD and choose recovery console. Type fixmbr and fixboot and see if that does the trick. Also make sure the XP partition is marked as active.

 

[hoang101]

And how can I do that, I remember came across that screen before, but now it's either go straigh throught window boot up or it will start to copy file to setup... and how to set it as active...

It's start as I want to format the drive to start up fresh , but window dont let me and prompt me that:
Windows cannot format this drive. Quit any disk utilities or other programs that are using this drive, and make sure that no window is displaying the contents of the drive. Then try formatting again.

So I went to Dos and it also said:
Format cannot run because the volume is in use by another
process. Format may run if this volume is dismounted first.
ALL OPENED HANDLES TO THIS VOLUME WOULD THEN BE INVALID.
Would you like to force a dismount on this volume? (Y/N)

After I type Y it prompt:
Volume dismounted. All opened handles to this volume are now invalid.

and I think because that force format , some how it's just asking to have WinXp in CD drive to boot. But I did not run any utili that I know of, I even disable that norton system work 2004 and it dont help...TIA