without changing my motherboard can anyone tell me how i can upgrade my celeron D processor to an Intel® Core™2 Quad processor or
Intel® Core™2 Duo processor
if i do need a motherboard change can anyone advise me on exactly which motherboard can meet my needs for the next 2 yrs...

anyhelp offered on the matter will be very much appreciated

The thing to do, rather than post your machine's specs here and have someone go searching would be to locate the make/model name/socket-type/etc etc etc of your motherboard, preferably on the manufacturers website (mine for example is an MSI motherboard, so I go to MSI website) and see if there is a compatibility list, which can tell you what other CPU's your board can handle, or even accomodate.

MSI for example again, can tell me all of the Intel CPU's I could possibly install in my motherboard without changing anything else. Perhaps your manufacturer offers a similar service.

Depending on your needs, perhaps the board you have now, will meet your needs for the next two years. Depends on how intensive work you need to do, and just how fast and powerful you want it . Motherboards themselves, IMHO, are 'relatively' inexpensive, for fairly powerful units these days.
Check out Newegg.com for some examples of what's out there.

GrapefruiT Girl has good advice. Dropping a new CPU into your PC is not necessarily a no-brainer, as the pin pattern of the CPU *must* match the mobo's socket. In other words, if the CPU has (for example) 50 pins and the mobo's CPU socket has 60 pins, obviously the PCU and mobo are incompatible.

If you want to retain the mobo, you need to make sure the new CPU is the same socket type. If you are going to get the new CPU, you'll probably need a new mobo, and you might as well buy new RAM as well (to take advantage of the faster speeds the newer mobo supports)

does me saying i have a dell dimension help any because i dont want to have to open up my pc @ the moment...but if not i'm always willing to...

Hmm.. No, that isn't necessary, really.. If you have the 'lshw' command, that will (probably) give you the motherboard model; it does for me anyhow. The model number of the board, combined with the model name of the machine and the current CPU name, should be enough to find the necessary info on the Dell site.
If you need 'lshw' you can get it from Sourceforge.

won't work, you'll need a new mobo that supports a 945 pinout.
ATCHUNG!!!: you'll need a new everything, lest you want to risk destroying a mobo, Dell psus _will_ destroy non dell mobos

Exactly, you'll need a socket 775 motherboard; which also means you'll need DDR2 RAM; and most 775 socket mobos support only two PATA devices, so if you have both a cd(rw) and a dvd(rw), you'll need to switch to SATA hard drives or buy a PCI IDE controller if you do want to keep any PATA hard drives, etc.

so i js need to buy a whole new pc w/ a bunch of new features? ok thats not so good...but anyway let me work w/ what i got but something really don't make sense to me on this machine when i had a 32 MB VRAM 128MB Ram 1.3GHz some "celeron equivalent AMD chip" and only 100MHz bus speed and i could run any linux distro smooth and w/ wat i got now i dont understand how i cant even run beryl to its best abilities...well I'll js see wat happens...and wat my pockets will allow me to

running Ubuntu 7 feisty and it works better on my laptop than the bloody dell...i think dell js lies about its specs...am sure of it...well now theres a quarter into the upgrade jar