Memory Upgrade questions

Below is my computer specs:

Inspiron Desktop 530S Slim Tower: Intel pentium dual-core processor e2140 (1MB L2, 1.60GHz,800 FBS)

Intel G33/G31

Window Vista Home Premiun - 32-Bit Operating Syatem

2GB DDR2 NON_ECC SDRAM 667MHz 9@ DIMMs)

I have  the following in hand:

CORSAIR XMS2 4GB PC2-6400 DDR2-800 Memory Kit TWIN 2X4096-6400C5. 

My computer have 4 slots for 1 GB each

I am wondering if it will be a problem if I install a 2GB memory stick in a 1 GB memory slot