otherwise you would not have been able to boot up into Windows 7. Also, the fact that you were able to boot into XP Safe Mode means the boot sector is fine.
See if the advice and link given in Carol's post below helps;
Since you are still able to use Windows 7 there should be no problem downloading anti-malware utilities and downloading and in particular, the utility called RKill can be copied over to your infected XP system, preferably the Desktop folder, so that you can run that from there, either in Normal Mode or Safe Mode.
Make sure you read all the guidance offered so that you know what you have to do.
Hope that sorts it for you.
I left me computer running the other day and when I came back it had rebooted. I run a dual boot with Win 7 / Xp.It
had booted to Win7, so I didn't think anything of it, just maybe an
anomaly or something.
I rebooted XP and found that my desktop had
completely disappeared. Also, the Quick start Icon had all disappeared
and I only had 2 programs in the START > PROGRAMS.One of those
programs was the XP Repair virus (which I have seen before on a friends
computer). In the bottom right hand corner was the little circle/with
an X through it icon (again the virus XP repair Icon). I didn't know
what to do considering that I couldn't do anything with my desktop. It
just sort of froze but I was still able to move the mouse around. The
drive whirred away.
I rebooted, trying SAFE MODE - and this really
surprised me - same thing. No desktop icon, only two program files and
the XP repair VIRUS. So I am at a loss of what to do. I can see all of the files on my other drive from WIN 7 (which I am using right now). I
have run malware and virus checkers, on track AT HOME and others to get
rid of the virus on the XP drive, but to no avail. Any idea how to get
the boot back? Thanks in advance.