Question : Problem: Can I use a 350W PSU with an MSI MS6433E Motherboard which used to have a 450W in it?

Question same as title :)

Answer : Problem: Can I use a 350W PSU with an MSI MS6433E Motherboard which used to have a 450W in it?

Use free tool online:

http://www.extreme.outervision.com/psucalculatorlite.jsp

Just make sure your system will not underpower with all devices ....