converting 64 bit to 32 bit on HDD partition

I partitioned earlier my 300 GB into C, D and E of 100 GB each, and loaded W7-32 bit on C and D, and Linux-64 on E. Now I want to bring the usage of E also under W7, and how do I do it?

So you don't want to use Linux anymore and you want to make that just another partition for windows to use is that correct? You can use a program Called Partition wizard Home addition which is a free download.
Once you've loaded it you can see your HDD with all it's partitions and alter "E" as to however you want.

Please explain in better detail about what your plans are for the E: partition.

If you want to remove Linux, you will run into issues because of the flavor of boot loader it installed and uses - either LILO or GRUB.

I'm unsure if Windows can access a Linux partition. I'm fairly certain it can not but may be possible with 3rd party software.