==System==
Operating System: Microsoft Windows XP Home Edition (5.2, Build 2600)
Processor: AMD Sempron(tm) Processor 3400+, MMX, 3DNow, ~1.8GHz
Memory: 446MB RAM
Page File: 554MB used, 499MB available
DirectX Version: DirectX 9.0c (4.09.0000.0904
Dell Model Number: ?
==Display==
Name: NVIDIA GeForce 6150 LE
Manufacturer: NVIDIA
Chip Type: 6150 LE
Approx. Total Memory: 256.0 MB
Main Driver: nv4_disp.dll
Version: 6.14.0010.9148
==Sound==
Name: SigmaTel Audio

Just downloaded the Sims 2 back onto my computer. And now I have a problem with it. Whislt playing a family, the play screen will flash a light blue, and then my sims and a few other thing will not be visible. Then when I move my mouse cursor or instruct a sim, everything things is fine for a few seconds, and then the problem occurs again. It a nuisance.

I only have the Sims 2, with no EP. And I have custom content..but hardly any since I just started again.
After work I'll post a picture of what happens and answer any other further question in about 4 hours. Thanks in advance.

Okay. I just went to the game, and it's working fine now? Weird.

Your specs are quite low, particularly your RAM, and you're using an unsupported integrated chip; so although you'll be able to play the basegame reasonably well, that's probably be the cause of the flashing - if so it'll probably come and go, and not be too much of an issue until the chip starts wearing out. I'd recommend you don't install any new EPs, though.