sis 305 windows XP pro. NTFS

PC : IBM 6049-C3A
RAM : 128MB
OS : WinXPProf.
Display Adapter : AGP : SiS305 2X 32MB VRAM

Problem : WinXP Prof. fails to load while pc is switched “ON”
if started in safe mode fails on the file names as “AGP440.SYS” ending up in blue screen error which says DISK_VOLUME_UNMOUNTABLE.
had been forced to get the replacement of the part since the system is under warranty period. but wanted to know if there’s any solution for the problem,in case the problem re-occurs after warranty period
NOTE:pls dont suggest for another OS ‘coz its out of my scope to do that.