By "Seven 64b", do you mean 64-bit Windows 7?
Theoretically, What OS is not important, 32-bit 0r 64-bit AutoCAD is. Even you use 64-bit OS, it is still possible to run 32-bit AutoCAD (well, you need a trick to install 32-bit ACad with 64-bit OS, but it is possible).
So, I assume you use AutoCAD 2010 64-bit (then you must use 64-bit OS).
To access data in Excel sheet or Access DB (*.xls, *.xlsx, *.mdb or *.accdb) with 64-bit application (Acad 64-bit), you need 64-bit driver. The good, old Jet Engine is only 32-bit, so you cannot use it. MS released its latest 64-bit Access engine, which you can use to access data in *.xls, *.xlsx, *.mdb, *.accdb without Excel/Access installed, just as you do with before with 32-bit application. The download link is here:
http://www.microsoft.com/downloads/en/details.aspx?displaylang=en&FamilyID=c06b8369-60dd-4b64-a44b-8...
Make sure you download the 64-bit version.
However, there is a big catch you must understand:
Even you use 64-bit OS, it is likely you may still use 32-bit MS office, including 32-bit Excel, and/or 32-bit Access. Yes, there is 64-bit Office since Office 2010. But MS itself recommends using 32-bit Office suite whenever possible. If you do use 32-bit Office, you CANNOT install 64-bit Access database engine! That is, if you have to use 64-bit Access engine to work with AutoCAD (64-bit), then you have to remove 32-bit MS office. If you have to use Office (Who do not?), you will need 64-bit Office. Then, if your Office apps rely on some 32-bit VBA code, then you are toasted...
This may be one of big reason people do not want to move to 64-bit Acad. One option would be to stop accessing data in Excel sheet/Access database directly, instead, moving data to a server-based database, such as SQL Server...