SIW - http://www.gtopala.com/
XP 32-bit works best with at least 2GB of RAM. Since you have an OEM MOBO then getting RAM anything greater than the MINIMUM supported speed is always going to get the 'Warning values...' reason 9.9/10 you cannot increase the DRAM/Memory Frequency nor the CAS timings. The BIOS says X Frequency and pulls the CAS 'SPD' timings from the RAM if encoded OR uses safe CAS timings for the X Frequency.
Therefore '200 MHz' is as fast as she's going unless the BIOS allows 'DDR2 667' ie 333 MHz setting.
The specs I found in a simple Google search:
MEMORY:
4 x 240-pin DDR2 DIMM
Dual-channel DDR2 memory architecture
Support DDR2 800/667/533/400 DDR2 SDRAM
GW Specs ->
http://support.gateway.com/s/PC/R/1015001R/1015001Rsp2.shtml
1GB/DIMM max with 4x1GB max capacity.
"nstalled: 3072 MB DDR2, 667 MHz, (PC2-5300) dual channel memory (two 1024 MB and two 512 MB modules)"
IF you have a sudden slowdown chances are some or 1 of your DIMM slots or RAM is dead.
1. Take the RAM in 'Slot 1' 512MB stick, remove the others, test boot the 'good' stick in ALL 4 DIMM slots. IF it boots then the DIMM slots are good. Next, use Isopropyl alcohol - clean the contacts on the RAM, dampen the contact and inset in ALL DIMM slots with ALL sticks, repeat twice per DIMM/RAM, remove and wipe-off, allow to dry 5 minutes, reinsert RAM and try booting. Some folks use a pencil eraser {BE CAREFUL} to remove oxidation.
2. Create a bootable CD/DVD of Memtest, use the ISO/zip file and burn the disk -> http://www.memtest.org/
Failures/Replacement RAM ->
http://www.crucial.com/store/listparts.aspx?model=GT5654&Cat=RAM ; don't bother getting NEW RAM is the DIMM slots are bad as above.
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Yes, I saw the following image. Not knowing the App it seems 3/4 of your DIMM slots are 'dead' or malfunctioning. The only cases for 3/4 suddenly not working: 1. PSU failure and ruined MOBO, 2. New short affecting DIMM pathways, 3. CPU failure, 4. 2 of the other sticks died before and suddenly a third (1GB) died and you're just noticing.