How do I get past The Parameter is Incorrect?

[Windows Central Question]

How do I get past " The Parameter is Incorrect"

Please Help, I downloaded Windows 10 preview on my Dell Laptop Studio 1747, running Windows 7 Ultimate, I have an i7 Dual Quad processor and 8GB RAM. Now I cannot log into my PC. Any suggestions as to how I can get back into my laptop without formatting and doing a reload.

Thanks
Stephen