It's been a long time since I went inside any PC, never this one until recently. If it helps, here's some info.
Win XP Home
SP-3
Pentium 4 running at 3.00 GHz
1 GB of ram (originally)
The original ram was in two "alternate" slots, call them #1 and #3 starting from the processor side of the bank. These two slots have white lock tabs, whereas the other two had black lock tabs.
When I added two additional SIMM's (also 512's, but likely not an exact match in terms of speed), I moved the original SIMM's to slots #1 and #2 and put the newer SIMM's in slots #3 and #4.
Now, when I booted, a BIOS message came up about mismatched SIMM's followed by what I "thought" was a suggestion of how to rectify this, and said hit enter. Which I did. System came up fine, but when I check properties, it only reflects 1.5 GB of memory.
Should I reshuffle these SIMM's somehow and if so, how?