Couldn't quit R session or couldn't quit RStudio

New to R and RStudio, got problem in operating RStudio.

I have a code sample about 53 lines, I could quit by typing "q()" or "quit()", but after I run any code(selected section or all codes), "q()" will not work as pic showing below

Or if I try to close RStudio browser, then a notification show up as below but never quit.

Any hint?

Thanks very much!

PS: RStudio verson: 0.99.948

-----1st Update------ @Mike Wise

Tried to get session info by typing "sessionInfo()" in console, unfortunately no response...pic below

Again, this case only happens after I run my code

-----2nd Update------- do the sessionInfo() before you run the code:

Info as below:

R version 3.2.3 (2015-12-10) Platform: x86_64-w64-mingw32/x64 (64-bit) Running under: Windows 7 x64 (build 7601) Service Pack 1

locale: 1 LC_COLLATE=English_United States.1252 LC_CTYPE=English_United States.1252 LC_MONETARY=English_United States.1252 [4] LC_NUMERIC=C
LC_TIME=English_United States.1252

attached base packages: 1 stats graphics grDevices utils
datasets methods base

loaded via a namespace (and not attached): 1 tools_3.2.3

My code:

# Linear Regression in R
# Copyright 2013 by Ani Katchova

mydata <- read.csv(file="E:\\Econometric Academy\\Linear Regression\\regression_auto.csv", header=TRUE, sep=",")
attach(mydata)

# Define variables
Y <- cbind(mpg)
X1 <- cbind(weight1)
X <- cbind(weight1, price, foreign)

# Descriptive statistics
summary(Y)
summary(X)

# Correlation among variables
cor(Y, X)

# Plotting data on a scatter diagram
plot(Y ~ X1, data = mydata)

# Simple linear regression 
olsreg1 <- lm(Y ~ X1)
summary(olsreg1)
confint(olsreg1, level=0.95)
anova(olsreg1)

# Plotting regression line
abline(olsreg1)

# Predicted values for dependent variable
Y1hat <- fitted(olsreg1)
summary(Y1hat)
plot(Y1hat ~ X1)

# Regression residuals
e1hat <- resid(olsreg1)
summary(e1hat)
plot(e1hat ~ X1)

# Multiple linear regression
olsreg2 <- lm(Y ~ X)
summary(olsreg2)
confint(olsreg2, level=0.95)
anova(olsreg2)

# Predicted values for dependent variable
Yhat <- fitted(olsreg2)
summary(Yhat)

# Regression residuals
ehat <- resid(olsreg2)
summary(ehat)