Upgrade from Celeron 1.7Ghz

[pcAnywhere]

At work we have an old PC (circa 2003) with an D845GBV chipset and a celeron 1.7 GHz (socket 478) and 256MB. We'd like to increase both the memory and the processor speed - but we cannot just replace the PC. The PC runs some specialised (but not too CPU hungry) equipment and an Access DB (about 2GB in size), but the most hungry software is likely to be the OS (Win 2K).

Intel's unfriendly website states that:
1) The chipset will support upto 2.8GHz Pentium 4 (533MHz)
2) Only 1GB of 266MHz DDR is "validated"

The questions I have are:
1) Does anyone know if Celeron D's are supported ? (as these use the 478 socket) and would this make a significant increase in operation?
2) Would a Pentium 4 (2.8GHz) be a significantly better option?
3) Can 2GB of DDR be used ?(there's some mention of this on the Intel site but not a lot)

Thanks

 

[pcAnywhere]

Thanks Lanz - pretty much what I suspected.

Now.. need to convince Global purchasing that "the auction site" is a suitable place to buy good from