I have windows xp and when i clicked on my computer an error message poped up saying this....

the instruction at "0x01ced065" referenced memory at "0x00000000". The memory could not be "written".

Please help me i have alot of important business files in my c: drive which i cannot access. I will greatly appreciate your help and support!!!!

On boot try hitting the f8 KEY
this gets you into safe mode or choice of boot up options mode in W2K no sure bout XP should be the same.
try the option boot in last known good configuration

After i do this will it work properly. I have windows xp so does it still work. Please help me fix this issue

i tried his and it didn't work. please i need your help im begging you.

no it may not work
this is just to see if you can turn back the system config to a workable one
it does not always work
if you still can't get in with this method try the safe mode
if you are running photoshop programs see if you can disable them temp.
last resort is repair with the install disc
I use W2K so procedure may be diff.
I ignore the first commands to repair and act like its a new install it will find the OS and prompt again to repair here is where I set it to repair
most cases it works long enough to find where the problem is

If the data on there is critical, i would take the drive out of the machine, and put it into another as a slave and try and get the data off first before you start messing around with trying to repair and whatnot.... and remember, after it's all sorted and the dust has settled (one way or another), regular backups are your bestest friend ever.

ever ever.