netver

The command netver lists all installed versions of the .Net framework.

.Net Framework Versions
v2.0.50727: Version 2.0.50727.4927 SP 2 installed
v2.0.50727/1031: Version 2.0.50727.4927 SP 2 installed
v3.0: Version 3.0.30729.4926 SP 2 installed
v3.0/Setup: Version 3.0.30729.4926
v3.0/Setup/1031: Version 3.0.30729.4926 SP 2 installed
v3.0/Setup/Windows Communication Foundation: Version 3.0.4506.4926
v3.0/Setup/Windows Presentation Foundation: Version 3.0.6920.4902
v3.5: Version 3.5.30729.4926 SP 1 installed
v3.5/1031: Version 3.5.30729.4926 SP 1 installed
v4/Client: Version 4.0.30319 installed
v4/Client/1033: Version 4.0.30319 installed
v4/Full: Version 4.0.30319 installed
v4/Full/1033: Version 4.0.30319 installed