The entire .NET platform was created with side-by-side installation in mind. You can have every version of VS (VS.NET 2002, VS.NET 2003, VS 2005, VS 2008, VS 2010, VS 2012, VS 2013) and every version of the .NET Framework (.NET 1.0, 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1) all installed on the same machine at the same time without issue. You can even install Express editions on the same machine with a paid-for edition of the same version.