Recommended configuration for Opera 7 without Java:
Pentium class system with 16 MB of RAM and at least 12 MB of free disk space
Windows 95 or higher operating system
28800 bps modem or higher connection
Please note that Java requires at least a Pentium 166 MHz processor, 32 MB of RAM and 65 MB free hard drive space to run.
I know that some people run it on very low spec PCs. Your's might be on the limit, but it is a light download without Java.