To install BI10gR2 (Oracle Discoverer tool) on Windows 7 you must first:
1)      Use an oracle installer compatible with Windows 7.  This can be provided via FTP.
Filename to download:
To install Discoverer Desktop
2)      Run setup.exe inside p5983622_10123_WINNT\Disk1
3)      Type ‘Y’ to continue at the command prompt
4)      Click NEXT at the welcome screen
5)      Change the source field to point to the product.xml file inside BI10gR2 (normally located inside:                  BI\10gR2\stage)
6)      Change the destination name to BI10gR2 (This is your chosen installation name or oracle home)
7)      Change the destination path to c:\oracle (The is your chosen installation path or oracle base)
8)      Click NEXT
9)      Check the CUSTOM option and click NEXT
10)   Leave checked ‘Custom’ and ‘Oracle Discoverer Desktop’,  uncheck all the other options and click               NEXT
11)    Click Install at the summary screen to install
You will need to configure the database connection for discoverer desktop after it’s installed.  This can be down within the tnsnames file. Local Windows explorer location (<destination path>\<destination name>\network\admin\tnsnames.ora)