I can help but I will need to know what you are running.
I will need the system specs.
Go here and run this report and add it as an attachment:
http://www.faronics.com/HTML/choose.asp
Get the software System Profiler.

This will get a snapshot of your hardware and settings.
You may have some hardware setting or the hardware drivers could be choking.

You could run a few tests to see if its video related. Even with a good card you can still get lockups and freezing at times.

Also check your ram. If the ram is not paging properly or gets a bit error it could cause lockups as the system will map out bad ram to help avoid crashing..

Check your system for reliability. There are several applications on the market for this.

Softimage needs to have minimum hardware met as well as the components communicationg properly.
I have ran into errors that seem like the OS but were in fact hardware related.
Bios settings can sometimes interfere.
IRQ’s can sometimes cause issues as well.

Its nessary to eliminate the OS/system of falts before running Softimage.
What I typically do is check the bios and learn exactly what each setting does.
Takes time but it eliminates the settings to be an issue.
next I ensure that the hardware is all locked down physically. a loose memory module or video card will cause you grief as it will cause failures intermittently.
next I test the throughput of the system from cpu to memory to hard drive and even to the video card. Most diagnostic software on the net does this and gives you what your system can handle in a report.
Once I know the OS and hardware are performing good then I fire up the software.
I load the example files and test each area and monitor the task manager for anomolies.

I run softimage on windows 7
My box is
I7 Core 2.6Ghz Quad core
12GB ram
1 TB HD by Seagate (NOTE: I was not aware of it at the time of first instal but this HD has a jumper that by default limits the speed of the drive to 1.5G/s which is ok for those who have older systems. I can run 3G/s and have to remove the jumper in order to get the speed boost. )
Video= 3700 Quadro FX

I have another system with vista on it.
The only issue I had was with large textures there were in .jpg format. They would show up as the noicon image.

I hope some of this helps.