Can I hook up my laptop to an older Pioneer home theatre 5.1 system?

Hey guys,

I have just purchased an Acer Aspire 5252-v440 laptop and wanted to know how, if possible, to hook it up to an older Pioneer home theatre 5.1 surround system. The pioneer surround has an optical in jack, as well as the standard green/blue/red ones component ins. no S/PDIF, however. I think my laptop can support dolby digital as windows media player plays in dolby. Plus, I have realtek hd sound drivers - assuming they support 5.1 at least.

Now, the issue is that I don't have (don't believe I have, have checked out the manual for my computer and it doesn't list a s/pdif port, nor do I remember seeing one on the unit). Is it still possible to hook up true surround sound?

My pioneer home theatre is an older model circa 2004-2005.

Thanks guys!