Can't dual boot after installing W7 retail with W7 RC

By reformatting the Vista partition, you also got rid of the boot files for W7 RC which were on that partition.
What you should have done was to use the W7 Easy Transfer Wizard to save your files and settings and then do a clean install.
Now it's too late and the only way I can think of, that may get your W7 RC working again, you are not going to like.
What you can try is to format your Windows 7 Retail instalation, use your W7 RC disk to boot Windows 7, run setup and choose repair startup.
Once you have the W7 RC running, use the W7 Easy Transfer Wizard to save your files and settings.
Next, reinstall again. Is it worth all the trouble? probably not, how much time is it going to take to setup things the way you want.

Could be worth a try, I didn't think of it to be truthfull, it's a bit early in the day here.
Give EasyBCD a go , nothing to loose and it won't harm anything.

Thanks. I'll take a look at EasyBCD. If that doesn't work, I think I'll just not worry about it. All I really need is some license keys, I think, and I probably have those stored somewhere. Next time I'll know better.

EasyBCD worked great. Took all of 3 minutes to fix the problem. Thanks!

Pre Win7, I used Vista Boot Pro, simple app to use to fix, check and backup boot config.

Found it also worked for Win 7, so just anotehr tool you may like to take note of.

More feature packed softwares aare like partition magic etc...